• Sleep Medicine and Psychophysiology
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• v.4 no.2
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• pp.191-200
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• 1997

Objectives : Periodic limb movements during sleep (PLMS) may cause arousals that may lead to non-restorative sleep. PLMS is characterized by long sleep latency, sleep fragmentation, frequent stage shifts, and rarity of stages 3/4 NREM sleep on polysomnography. However, controversies have existed and it still remains to be elaborated whether PLMS actually causes insomnia, since normal persons happen to have PLMS. Clinically, it would be crucial to know factors which might disturb sleep in PLMS. We became interested in Coleman's theory(1980) that invariant periodic movements disturb patients' sleep less. Though, Coleman's study seems to have been confounded by including PLMS patients with various co-morbid sleep disorders. Therefore, we attempted to study in patients only with PLMS the effects of movement patterns on sleep architecture. Methods : In 27 patients diagnosed as having PLMS only with clinical interview and nocturnal polysomnography, we studied the relationship between the movement patterns such as mean duration and variability of periodic limb movement's interval and the sleep architecture variables. Results : The shorter and the more regular the limb movement intervals were, the fewer arousals followed. The movement intervals of the older patients were shorter and more regular than the younger patients. The probability of the accompanying arousal with each limb movement increased as the duration and variance of the movement intervals increased. It decreased as the age and the frequency of limb movements increased. Among these factors the most significant one was the mean duration of the movement intervals. In other words, the shorter the movement intervals were, the less disturbed sleep was. Conclusion : PLMS frequency increases with aging but the probability of the accompanying arousal with each movement decreases with aging. Sleep-disturbing effects of PLMS depends more on the duration and variability of movement intervals than the PLMS frequency.

• Journal of the Ergonomics Society of Korea
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• v.22 no.4
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• pp.15-25
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• 2003

Recent studies indicate potential links between various psychosocial factors and work-related musculoskeletal disorders (WMSDs). In this research, the effects of job stressors on the WMSDs symptoms were investigated using questionnaire in the largest automotive company in Korea. It was found that perception of workload, over time and shift work, and working using powered hand tools were significant factors for the symptoms of WMSDs, along with smoking habit, periodic exercise, and interpersonal relationship. Practical applications of this research include practitioners taking into account psychosocial work factors and job stress in their efforts to reduce and control WMSDs.

• Childhood Kidney Diseases
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• v.20 no.2
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• pp.50-56
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• 2016

Purpose: Nocturnal enuresis (NE) is one of the most common problems in childhood. NE has a multifactorial etiology and is influenced by sleep and arousal mechanisms. The aim of the present study was to prospectively evaluate sleep problems and patterns in children with NE compared with normal healthy controls. Methods: Twenty-eight children with NE and 16 healthy controls were included in the study. To evaluate sleep habits and disturbances, parents and children filled out a questionnaire that included items about sleep patterns and sleep-related behaviors prior to treatment for NE. Demographic factors and other data were compared for the two groups based on the responses to the sleep questionnaire. Results: Night awakening, sleepwalking, and periodic limb movements were more prevalent in children with NE, but symptoms of sleep-disordered breathing were not increased in this group. There were statistically significant differences in periodic limb movements and daytime sleepiness between the two groups. Conclusion: Children with NE seemed to have more sleep problems such as night awakening, sleepwalking, and periodic limb movements. In addition, a higher level of daytime sleepiness and hyperactivity in patients with NE suggested a relationship between NE and sleep disorders.

• Journal of the Korean institute of surface engineering
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• v.39 no.5
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• pp.223-228
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• 2006

The current efficiency of copper anode containing impurities in copper sulfate solution for electrorefining was studied at various current type such as direct current, variable current and periodic reverse current. The passivity behavior was investigated by galvanostatic technique. The results obtained were that current efficiency of variable current was higher than those of direct current and periodic reverse current. The increased current efficiency could be explained by the formation of slime structure with lower average resistance due to variable current. The frequency of various factors in variable current condition has a greatest effect on current efficiency. It appeared that frequency increased current efficiency when increased from 1 to 4, but further increases did not have an effect.

• Journal of Korea Game Society
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• v.4 no.3
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• pp.77-84
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• 2004

Game environment, game map and background graphic design is very important elements and factors that support fun, look & feel, immersion and player's acting fields. In this paper we defined elements of game background environment. And then make an investigation and refer to sundry records and books, we described elements of periodic environments, historic environments, natural environments, artificial environments, cultural environments, virtual environments, weather environments. Especially, the study suggests the model of game environment desgin to apply game map and game background graphic design.

• Safety and Health at Work
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• v.12 no.4
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• pp.505-510
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• 2021

Background: Factors related to root causes can cause commonly occurring accidents such as falls, slips, and jammed injuries. An important means of reducing the frequency of occupational accidents in small- to medium-sized enterprises (SMSEs) of South Korea is to perform intensity analysis of the root cause factors for accident prevention in the cause and effect model like decision models, epidemiological models, system models, human factors models, LCU (life change unit) models, and the domino theory. Especially intensity analysis in a robot system and smart technology as Industry 4.0 is very important in order to minimize the occupational accidents and fatal accident because of the complexity of accident factors. Methods: We have developed the modern cause and effect model that includes factors of root cause through statistical testing to minimize commonly occurring accidents and fatal accidents in SMSEs of South Korea and systematically proposed educational policies for accident prevention. Results: As a result, the consciousness factors among factors of root cause such as unconsciousness, disregard, ignorance, recklessness, and misjudgment had strong relationships with occupational accidents in South Korean SMSEs. Conclusion: We conclude that the educational policies necessary for minimizing these consciousness factors include continuous training procedures followed by periodic hands-on experience, along with perceptual and cognitive education related to occupational health and safety.

• The KIPS Transactions:PartA
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• v.11A no.7 s.91
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• pp.483-488
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• 2004

For real-time applications, the underlying operating system (0S) should support timeliness guarantees of real-time tasks. However, most of current operating systems do not provide timely management facilities in an efficient way. There could be two approaches to support timely management facilities for real-time applications: (1) by modifying 0S kernel and (2) by Providing a middleware without modifying 0S. In our approach, we adopted the middleware approach based on the TMO (Time-triggerred Message-triggered Object) model which is a well-known real-tine object model. The middleware, named TMSOM (TMO Support Middleware) has been implemented on various OSes such as Linux and Windows XP/NT/98. In this paper, we mainly consider TMOSM implemented on Linux(TMOS/Linux). Although the real-time schedul-ing aIgorithm used in current TMOSM/Linux can produce an efficient real-time schedule, it can be improved for periodic real-time tasks by considering several factors. In this paper, we discuss those factors and propose an improved real-time scheduling algorithm for periodic real-time tasks, In order to simulate the performance of our algorithm, we measure timeliness guarantee rate for periodic real-time tasks. The result shows that the performance of our algorithm is superior to that of existing algorithm. Additionally, the proposed algorithm can improve system performance by making the structure of real-time middleware simpler.

• Journal of Korean Academy of Nursing
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• v.33 no.6
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• pp.705-712
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• 2003

Purpose: The purpose of this study was to explore factors that influence care dependency of institutionalized patients with dementia. Method: This study utilized descriptive correlational design. The convenience sample was composed of 110 residents with dementia of two long-term care facilities in Korea. Stepwise multiple regression was used to identify significant factors influencing care dependency in patients with dementia. Care dependency was measured using the Care Dependency Scale, Korean version(CDS-K). Cognition was measured by the MMSE-K. Functional disability was measured by the PULSES Profile. Behavioral dysfunction was measured by the modified E-BEHAVE AD. Result: Care dependency was significantly influenced by cognition, functional disability, behavioral dysfunction, and duration of dementia. This regression model explained 61 % of the variances in care dependency. Cognition explained 37% of the variances, and functional disability explained 21% of the variances. Conclusion: Results of this study suggest that professional caregivers intervene more effectively in caring for their patients with dementia by recognizing the patients cognitive, functional, behavioral disability, and its periodic change. Individually, remaining abilities-focused intervention should be applied to enhance patient to be dependent and to prevent unnecessary independency.

• Journal of the Korea Safety Management & Science
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• v.10 no.3
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• pp.19-27
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• 2008

Since 1995, the facility of class 1 and 2, classified by law had been subject to system of post maintenance management where periodic safety inspection and diagnosis to identify any problems and to take appropriate measures as a matter of urgency. Although the standards and systems had been revised many times for continuous improvement due to surrounding environmental factors, the technical factors and other factors for improvements, continuous researches and efforts are needed to ensure even higher effectiveness. Furthermore, the consciousness of the management body that executes and implements such improvements for facility management is most important. Therefore in this study, through such analysis, more realistic management consciousness review was performed. Also the direction for improvements is proposed, to carry out more effective facility safety management systems implementation.

• The Journal of the Acoustical Society of Korea
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• v.15 no.1
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• pp.5-9
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• 1996

Vibrato means periodic variations of various characteristics in sound wave. Because it causes special tonal effects, it plays and important role in musical performance. But when we examine the cases of scientific study about the vibrato that has been done until now, the cases were focused just on acoustic analysis of vibrato, so they didn't disclose the correlation between the results of analysis and the musical factors concerning actual performance. So this paper attempts to analyze violin vibrato acoustically, and find out the interrelation between the results and the various musical factors of violin performance.